The invention relates to a bipolar coagulation and cutting device for use in endoscopic surgeries with two U-shaped jaws, which are supported at the end of an operating shaft so as to be movable relative to each other for coagulating tissue engaged between the jaws and a cutting structure for severing the coagulated tissue.
Such a combined instrument is known from the information leaflet of the Cabot Technology Corporation,2150 Cabot Boulevard West, Langhorne Pa. 19047, USA, which was distributed in 1995. The instrument described therein includes a grasping structure comprising two branches, which are U-shaped and along which tissue is coagulated. Subsequently, a cutting blade is moved forwardly through the grasping and coagulation structure, which cuts the tissue between the coagulated areas.
A combination instrument, which is operated in principle in the same manner, is disclosed in U.S. Pat. No. 5,445,638. Both instruments have in common that the grasping structure is also used for bipolar coagulation and, after coagulation, the intermediate tissue area is cut mechanically by a cutting blade. This procedure is performed by the surgeon. The forces required for the cutting of the tissue have to be transmitted from one end of the instrument to the other.
It is the object of the present invention to provide a combined instrument for the endoscopic surgery with which the tissue is grasped and safely engaged by U-shaped jaws formed by branches and, at the same time, a reliable line coagulation can be performed in accordance with the shape of the branches and, afterwards, the tissue is severed in the coagulated intermediate area between the U-shaped clamp branches by a cutting device requiring minimal force application.
In a bipolar coagulation and cutting device for endoscopic surgery with a proximal operating part and a distal grasping part interconnected by a shaft, the distal grasping part includes jaws, each having two spaced branches supported on flexible wires. The jaws are held apart but are movable toward each other by actuating means extending along the shaft for the engagement of tissue between the jaws. HF energy can be supplied for the coagulation of the tissue engaged between the jaws. A wire electrode is also mounted on the shaft so as to be movable by the actuating means between the spaced branches of the jaws for cutting, by HF energy application, the coagulated tissue engaged between the jaws.
Preferably, means are provided for guiding the branches of the grasping jaws and of the cutting device in a stable manner. With a blade-like configuration of the cutting electrode, the tissue separation is further facilitated. The two branches of the coagulation structure are curved or wave-like for improved engagement of the tissue. Both branches are disposed on top of one another in parallel when they are pressed together. The branches may be straight or they may be curved. For the safe engagement of the tissue, it is often advantageous if one of the two branches is angled with respect to the other and extends beyond the other branch when the two branches are completely folded together. If one of the branches is angled in a hook-like fashion such that, when folded together, the jaw with the hook-shaped branch overlaps the other, the tissue is firmly engaged by the jaws. Such firm engagement could be obtained with prior art grasping devices only by the provision of corrugations by which the engaged tissue has often been damaged.
The main advantage of the arrangement according to the invention is that, in addition to the grasping and coagulation procedure by high frequency energy application in accordance with the invention, the tissue is also severed by the application of high frequency energy by means of a particularly shaped cutting electrode. This is particularly advantageous for relatively small severing lengths ( less than 5 mm) since a mechanical cutting plate is guided with a relatively high tolerance. It cannot be accurately controlled since, during forward movement of the cutting blade, its position is not easily visible. The surgeon does not need to apply cutting forces with the arrangement according to the invention, and can therefore better concentrate on the guidance and movement of the combined instrument.
With the line-like configuration of the two clamping jaw branches and a corresponding forwardly limited and closed coagulation line impressed into the tissue, the enclosed area can then easily be fully severed. The two branches may be straight or curved and, in addition, both may be wave-shaped. The shape of the two branches may vary in reasonable ways depending on the application.